HNCOCa^(+)的光谱和成键:基质隔离和计算研究  

Spectroscopic Identification and Bonding Properties of HNCOCa^(+):a Matrix Isolation and Computational Study

作　　者：蒋鑫 孙蓓蓓 王冠军 王丽娜[1] 曾小庆 周鸣飞 Xin Jiang;Beibei Sun;Guanjun Wang;Lina Wang;Xiaoqing Zeng;Mingfei Zhou(Department of Chemistry,Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials,Fudan University,Shanghai 200438,China)

机构地区：[1]复旦大学化学系,上海市分子催化和功能材料重点实验室,上海200438

出　　处：《Chinese Journal of Chemical Physics》2024年第2期361-368,I0053-I0058,I0104,共15页化学物理学报（英文）

基　　金：This work was supported by the National Natural Science Foundation of China(No.22025301,No.22273012,and No.22321003).

摘　　要：金属(异)氰化物是星际介质中金属化合物的主要组成部分.它们的氧化物-金属(异)氰酸作为潜在的星际分子也备受关注.然而,作为金属(异)氰酸的前体,阳离子HNCOM^(+)的研究却非常有限.本文通过红外光谱、同位素取代和量子化学计算,对HNCOCa^(+)进行了详细研究.为了进行对比,还探索研究了HNCOBe^(+)和HNCOBa^(+)阳离子.结果表明,金属阳离子与HNCO反应可以生成HNCOCa^(+)和HNCO-Be^(+),但未观测到HNCOBa^(+)的生成.HNCOCa^(+)中非对称和对称NCO伸缩振动频率(2362.6和1330.4 cm^(-1))高于自由的HNCO分子(2268.5和1320.3 cm^(-1)),但比HNCOBe^(+)(2426.4和1355.2 cm^(-1))低.这些频率的变化是由HNCOBe^(+)和HNCOCa^(+)中NCO单元内的电荷极化导致.成键分析表明,HNCO-Be^(+)键倾向于共价性质(54%),而HNCO-Ca^(+)键则具有较高的静电性质(57%).在HNCO-Ba^(+)键中,占主导的静电相互作用(64%)导致了低的O-Ba键能,这解释了其在实验中未被制备的原因.Metal(iso)cyanides dominate the molecular inventory of metal-bearing species in the interstellar medium.Their oxide counterparts,metal(iso)cyanates,have potential as interstellar molecules and have received significant attention.However,cationic complexes HNCOM^(+)as precursors to metal(iso)cyanates are rarely studied.Herein,we investigated HNCOCa^(+)by exploiting infrared spectrometry with isotopic substitutions and quantum chemical calculations.For comparison,the light and heavy alkaline earth metal cationic complexes HNCOBe^(+)and HNCOBa^(+)were also explored.HNCOCa^(+)and HNCOBe^(+)rather than HNCOBa^(+)can be experimentally generated by the reactions of metal cations with HNCO.The observed antisymmetric and symmetric NCO stretching vibrations in HNCOCa^(+)(2362.6 and 1330.4 cm^(−1))are higher than those in free HNCO(2268.5 and 1320.3 cm^(−1))but lower than those in HNCOBe^(+)(2426.4 and 1355.2 cm^(−1)).These shifts can be explained by the charge polarization within the NCO fragment in HNCOBe^(+)and HNCOCa^(+).Bonding analysis suggests that HNCO−Be^(+)bond favors covalent character(54%)while HNCO−Ca^(+)bond has higher electrostatic character(57%).The dominant electrostatic interaction(64%)in HNCO−Ba^(+)bond results in the low bond energy,which might account for its absence in experiments.

关 键 词：钙 HNCO 成键分析 基质隔离 振动光谱 

分 类 号：O64[理学—物理化学]